The Briggs-Rauscher oscillatory reaction method as a “fingerprint” for bentonite clays

Abstract

The oscillatory Briggs-Rauscher (BR) reaction was applied on solid insoluble materials - bentonite clays from different deposits: Wyoming (Swy-2), Texas (STx-1b), Idaho (SbId-1), Arizona (SAz-2), Bogovina and Mečji Do, last two from Serbia. Under the same BR experimental conditions, the addition of identical masses (0.25 g) of particular clay resulted in different effects on oscillatory dynamics. There is a prolongation, quenching, or no influence on oscillatory dynamics. Additionally, in the case of different masses of clay added, the response of the BR oscillating system resulted in a complex behavior pattern (oscillatory period vs. bentonite mass). This complex behavior pattern (firstly obtained by using clays in BR), could be applied as a fingerprint for bentonite identification. It is supported by facts that montmorillonite/beidellite ratio, cation exchange capacity, principal exchange cation, the extent of iron leaching in the acidic environment of BR reaction, and specific surface area of each used clays were not exclusively responsible for observed behavior in oscillatory reaction. This means that all bentonite’s properties combined are probably responsible for behavior obtained in oscillatory reaction, making BR reaction as an easily available and economical method for the identification of bentonite clay origin